Method for etching organic low-k dielectric using ammonia, NH3, as an
active etchant. Processes using ammonia results in at least double the
etch rate of organic low-k dielectric materials than processes using
N2/H2 chemistries, at similar process conditions. The difference is due
to the much lower ionization potential of NH3 versus N2 in the process
chemistry, which results in significantly higher plasma densities and
etchant concentrations at similar process conditions.